Bone-derived implantable devices and tool for subchondral treatment of joint pain

ABSTRACT

Implantable devices for the surgical treatment of bone, and particularly to a bone defect at a joint region, and even more particularly at the subchondral bone level of the joint region, are disclosed. The implantable devices may be formed of a bone material, and configured to serve the dual functions of providing mechanical strength and structural integrity to the area to be treated, while also facilitating the dispersal of a flowable material in the same area. Associated delivery tools are also provided.

CROSS REFERENCE TO RELATED APPLICATIONS

This application claims priority to U.S. Provisional No. 61/354,100filed Jun. 11, 2010, and entitled “IMPLANTABLE DEVICES AND RELATEDDELIVERY TOOLS,” and U.S. Provisional No. 61/263,170 filed Nov. 20,2009, and entitled “METHOD FOR TREATING JOINT PAIN AND ASSOCIATEDINSTRUMENTS,” which are herein incorporated by reference in theirentirety.

This application also relates to co-pending and co-owned U.S. patentapplication Ser. No. 12/950,355, filed Nov. 19, 2010 and entitled“SUBCHONDRAL TREATMENT OF JOINT PAIN,” the content of which is hereinincorporated in its entirety by reference.

FIELD

The present invention relates to devices for the surgical treatment ofbone tissue, and more particularly to implantable devices and relateddelivery tools for the surgical repair or treatment of damaged bonetissue, especially at or near a joint. Even more particularly, theimplantable device can be formed from a bone material.

BACKGROUND

Human joints, in particular the knee, hip and spine, are susceptible todegeneration from disease, trauma, and long-term repetitive use thateventually lead to pain. Knee pain, for example, is the impetus for awide majority of medical treatments and associated medical costs. Themost popular theory arising from the medical community is that knee painresults from bone-on-bone contact or inadequate cartilage cushioning.These conditions are believed to frequently result from the progressionof osteoarthritis, which is measured in terms of narrowing of the jointspace. Therefore, the severity of osteoarthritis is believed to be anindicator or precursor to joint pain. Most surgeons and medicalpractitioners thus base their treatments for pain relief on this theory.For example, the typical treatment is to administer pain medication, ormore drastically, to perform some type of joint resurfacing or jointreplacement surgery.

However, the severity of osteoarthritis, especially in the knee, hasbeen found to correlate poorly with the incidence and magnitude of kneepain. Because of this, surgeons and medical practitioners have struggledto deliver consistent, reliable pain relief to patients especially ifpreservation of the joint is desired.

Whether by external physical force, disease, or the natural agingprocess, structural damage to bone can cause injury, trauma,degeneration or erosion of otherwise healthy tissue. The resultantdamage can be characterized as a bone defect that can take the form of afissure, fracture, lesion, edema, tumor, or sclerotic hardening, forexample. Particularly in joints, the damage may not be limited to a bonedefect, and may also include cartilage loss (especially articularcartilage), tendon damage, and inflammation in the surrounding area.

Patients most often seek treatment because of pain and deterioration ofquality of life attributed to the osteoarthritis. The goal of surgicaland non-surgical treatments for osteoarthritis is to reduce or eliminatepain and restore joint function. Both non-surgical and surgicaltreatments are currently available for joint repair.

Non-surgical treatments include weight loss (for the overweightpatient), activity modification (low impact exercise), quadricepsstrengthening, patellar taping, analgesic and anti-inflammatorymedications, and with corticosteroid and/or viscosupplements. Typically,non-surgical treatments, usually involving pharmacological interventionsuch as the administration of non-steroidal anti-inflammatory drugs orinjection of hyaluronic acid-based products, are initially administeredto patients experiencing relatively less severe pain or jointcomplications. However, when non-surgical treatments prove ineffective,or for patients with severe pain or bone injury, surgical interventionis often necessary.

Surgical options include arthroscopic partial meniscectomy and loosebody removal. Most surgical treatments conventionally employ mechanicalfixation devices such as screws, plates, staples, rods, sutures, and thelike are commonly used to repair damaged bone. These fixation devicescan be implanted at, or around, the damaged region to stabilize orimmobilize the weakened area, in order to promote healing and providesupport. Injectable or fillable hardening materials such as bonecements, bone void fillers, or bone substitute materials are alsocommonly used to stabilize bone defects.

High tibial osteotomy (HTO) or total knee arthroplasty (TKA) is oftenrecommended for patients with severe pain associated withosteoarthritis, especially when other non-invasive options have failed.Both procedures have been shown to be effective in treating knee painassociated with osteoarthritis.

However, patients only elect HTO or TKA with reluctance. Both HTO andTKA are major surgical interventions and may be associated with severecomplications. HTO is a painful procedure that may require a longrecovery. TKA patients often also report the replaced knee lacks a“natural feel” and have functional limitations. Moreover, both HTO andTKA have limited durability. Accordingly, it would be desirable toprovide a medical procedure that addresses the pain associated withosteoarthritis and provides an alternative to a HTO or TKA procedure.

Yet, even now there still remains a concern with the introduction of animplantable device made of foreign materials (i.e., metals, polymers orcombinations of both) into the human body. And although there exists anumber of biocompatible metals and polymers currently consideredacceptable for short to long-term placement within a patient, therecontinues to be questions associated with the interaction between themedical device and the tissues and physiological systems of the patient.Moreover, in cases where the implantable device is being placed into adynamic environment such as in or near a bone joint, where differentforces are acting upon the area to be treated, the biomechanical risksof introducing a material having different physical properties thannaturally occurring bone are still unknown. What is known, however, isthat the implantable device should mimic as close as possible tonaturally occurring bone in both its biomechanical and physiologicalfunctions as well as its biological properties.

Accordingly, it is desirable to provide implantable devices that canprovide mechanical strength and structural integrity to the area to betreated, while also being as physiologically and biologically compatibleas possible to reduce or eliminate any potential negative effects to thepatient. It would also be beneficial to provide such devices having theability to facilitate the dispersal of hardening or augmentationmaterial in the same area. It is further desirable to provideimplantable devices that are configured for the treatment or repair ofdamaged bone tissue particularly at the joints, and even moreparticularly at the subchondral bone level.

SUMMARY

The present disclosure provides implantable devices formed of bonematerial for placement inside bone. The devices are configured toprovide mechanical strength and structural integrity to bone tissue tobe treated, while also being physiologically and biologicallycompatible. In addition, the devices facilitate the dispersal ofhardening or augmentation material in the same area. These implantabledevices are configured for the treatment or repair of damaged bonetissue at the joints, and even more particularly at the subchondral bonelevel. Also provided are delivery tools for delivering the devices tothe area of bone to be treated.

In one exemplary embodiment, an implantable device for treatment of abone defect is disclosed. The device may include a first, leading end, asecond, trailing end, and a main body extending between the ends. Acentral opening may extend through the length of the main body, and achannel may be provided in fluid communication with the central openingto allow extrusion of a flowable material from the central opening tooutside the main body. The device may be formed of bone material, suchas allograft material.

In another exemplary embodiment, a method of treating a bone defect isprovided. The method comprises the steps of providing an implantabledevice having a first, leading end, a second, trailing end, and a mainbody extending between the ends, a central opening extending through thelength of the main body, and a channel in fluid communication with thecentral opening to allow extrusion of a flowable material from thecentral opening to outside the main body, the device being formed ofallograft material. The implantable device may be implanted adjacent thebone defect. A flowable material may be introduced through the centralopening and out of the channel. The flowable material may be allowed toextrude away from the device.

In another exemplary embodiment, an implantable device for treatment ofa bone defect is disclosed. The device may include a first, leading end,a second, trailing end, and a main body extending between the ends. Themain body may comprise at least one recess extending down at least aportion of the main body. The device may be formed of a bone material,such as an allograft material.

It is to be understood that both the foregoing general description andthe following detailed description are exemplary and explanatory onlyand are not restrictive of the disclosure. Additional features of thedisclosure will be set forth in part in the description which follows ormay be learned by practice of the disclosure.

BRIEF DESCRIPTION OF THE DRAWINGS

The accompanying drawings, which are incorporated in and constitute apart of this specification, illustrate several embodiments of thedisclosure and together with the description, serve to explain theprinciples of the disclosure.

FIG. 1 is a perspective view of an exemplary embodiment of animplantable device of the present invention;

FIG. 2A is a perspective view of the device of FIG. 1 with an exemplaryembodiment of an insertion tool of the present invention;

FIG. 2B shows the device and the associated insertion tool of FIG. 2Afully engaged;

FIG. 2C shows the device and the associated insertion tool of FIG. 2Apartially disengaged;

FIGS. 3A-3Q illustrate an exemplary method of delivering the implantabledevice of FIG. 1 into a bone;

FIGS. 4A-4C illustrate another exemplary method of delivering a flowablematerial into the implantable device of FIG. 1 into a bone;

FIGS. 5A-5B illustrate another exemplary embodiment of an implantabledevice of the present invention;

FIG. 6A shows an inserter tool with the device of FIGS. 5A and 5B;

FIG. 6B shows a delivery tool with the inserter tool and device of FIG.6A;

FIG. 7A shows the device of FIGS. 5A and 5B with an injection port;

FIG. 7B shows the device of FIGS. 5A and 5B with the injection portattached to the device;

FIG. 8 illustrates yet another exemplary embodiment of an implantabledevice of the present disclosure; and

FIGS. 9 and 10 illustrated yet even more exemplary embodiments ofimplantable devices of the present disclosure.

DESCRIPTION OF THE EMBODIMENTS

The present disclosure provides a methodology, devices and instrumentsfor diagnosing and treating joint pain to restore natural joint functionand preserving, as much as possible, the joint's articular and cartilagesurface. Treatments through the joint that violate the articular andcartilage surface often weaken the bone and have unpredictable results.Rather than focusing on treatment of pain through the joint, theembodiments diagnose and treat pain at its source in the subchondralregion of a bone of a joint to relieve the pain. Applicants havediscovered that pain associated with joints, especially osteoarthriticjoints, can be correlated to bone defects or changes at the subchondrallevel rather than, for example, the severity of osteoarthriticprogression or defects at the articular surface level. In particular,bone defects, such as bone marrow lesions, edema, fissures, fractures,hardened bone, etc. near the joint surface lead to a mechanicaldisadvantage and abnormal stress distribution in the periarticular bone,which may cause inflammation and generate pain. By altering the makeupof the periarticular bone (which may or may not be sclerotic) inrelation to the surrounding region, it is possible to change thestructural integrity of the affected bone and restore normal healingfunction, thus leading to a resolution of the inflammation surroundingthe defect.

Applicants have discovered that treatment of the bone by mechanical andbiological means to restore the normal physiologic stress distribution,and restore the healing balance of the bone tissue at the subchondrallevel, is a more effective way of treating pain than conventionaltechniques. That is, treatment can be effectively achieved bymechanically strengthening or stabilizing the defect, and biologicallyinitiating or stimulating a healing response to the defect. Accordingly,the present disclosure provides methods, devices, and systems for asubchondral procedure. This procedure and its associated devices,instruments, etc. are also marketed under the registered trademark nameof SUBCHONDROPLASTY™. The SUBCHONDROPLASTY™ procedure is a response to adesire for an alternative to patients facing partial or total kneereplacement.

In general, the SUBCHONDROPLASTY™ or SCP™ technique is intended to bothstrengthen the bone and stimulate the bone. In SCP™, bone fractures ornon-unions are stabilized, integrated or healed, which results inreduction of a bone defect, such as a bone marrow lesion or edema. Inaddition, SCP™ restores or alters the distribution of forces in a jointto thereby relieve pain. SCP™ can be performed arthroscopically orpercutaneously to treat pain by stabilizing chronic stress fracture,resolving any chronic bone marrow lesion or edema, and preserving, asmuch as possible, the articular surfaces of the joint. SUBCHONDROPLASTY™generally comprises evaluating a joint, for example, by taking an imageof the joint, detecting the presence of one or more subchondral defects,diagnosing which of these subchondral defects is the source of pain, anddetermining an extent of treatment for the subchondral defect. Thepresent technique is particularly suited for treating chronic defects orinjuries, where the patient's natural healing response has not resolvedthe defect. It should be noted, however, that the technique is equallyapplicable to treatment of defects in the subchondral region of bonewhere the defect is due to an acute injury or from other violations. Thepresent disclosure provides several exemplary treatment modalities forSCP™ for the different extents of treatment needed. Accordingly, amedical practitioner may elect to use the techniques and devicesdescribed herein to subchondrally treat any number of bone defects as hedeems appropriate.

In some embodiments, detection and identification of the relevant bonemarrow lesion or bone marrow edema (BML or BME) can be achieved byimaging, e.g., magnetic resonance imaging (MRI), X-ray, manualpalpation, chemical or biological assay, and the like. A T1-weighted MRIcan be used to detect sclerotic bone, for example. Another example isthat a T2-weighted MRI can be used to detect lesions, edemas, and cysts.X-ray imaging may be suitable for early-stage as well as end-stagearthritis. From the imaging, certain defects may be identified as thesource of pain. In general, defects that are associated with chronicinjury and chronic deficit of healing are differentiated from defectsthat result, e.g., from diminished bone density. SCP™ treatments areappropriate for a BML or BME that may be characterized as a bone defectthat is chronically unable to heal (or remodel) itself, which may causea non-union of the bone, stress or insufficiency fractures, andperceptible pain. Factors considered may include, among other things,the nature of the defect, size of the defect, location of the defect,etc. For example, bone defects at the edge near the articular surface orperiphery of a joint may be often considered eligible for treatment dueto edge-loading effects as well as the likelihood of bone hardening atthese locations. A bone defect caused by an acute injury would generallybe able to heal itself through the patient's own natural healingprocess. However, in such situations where the bone defect is due to anacute injury and either the defect does not heal on its own, or themedical practitioner decides that the present technique is appropriate,SCP™ treatments can be administered on acute stress fractures, BML orBME, or other subchondral defects, as previously mentioned.

According to the embodiments, the SCP™ treatment may continue aftersurgery. In particular, the patient may be monitored for a change inpain scores, or positive change in function. For example, patients arealso checked to see when they are able to perform full weight-bearingactivity and when they can return to normal activity. Of note, ifneeded, the SCP™ procedure can be completely reversed in the event thata patient requires or desires a joint replacement or other type ofprocedure. The SCP™ treatment may also be performed in conjunction withother procedures, such as cartilage resurfacing, regeneration orreplacement, if desired.

The present disclosure provides a number of treatment modalities, andassociated devices, instruments and related methods of use forperforming SUBCHONDROPLASTY™. These treatment modalities may be usedalone or in combination.

In one treatment modality, the subchondral bone in the region of thebone marrow lesion or defect can be strengthened by introduction of ahardening material, such as a bone substitute, at the site. The bonesubstitute may be an injectable calcium phosphate ensconced in anoptimized carrier material. In SCP™, the injected material may alsoserve as a bone stimulator that reinvigorates the desired acute bonehealing activity. In addition, some of the soft bone tissue may becompacted prior to insertion of the material.

For example, polymethylmethacrylate (PMMA) or calcium phosphate (CaP)cement injections can be made at the defect site. PMMA injection mayincrease the mechanical strength of the bone, allowing it to withstandgreater mechanical stresses. CaP cement injection may also increase themechanical strength of the bone, while also stimulating the localizedregion for bone fracture repair. In one embodiment, the injection can bemade parallel to the joint surface. In another embodiment, the injectioncan be made at an angle to the joint surface. In yet another embodiment,the injection can be made below a bone marrow lesion.

In another treatment modality, the subchondral bone region can bestimulated to trigger or improve the body's natural healing process. Forexample, in one embodiment of this treatment modality, one or more smallholes may be drilled at the region of the defect to increase stimulation(e.g., blood flow, cellular turnover, etc.) and initiate a healingresponse leading to bone repair. In another embodiment, after holes aredrilled an osteogenic, osteoinductive, or osteoconductive agent may beintroduced to the site. Bone graft material, for example, may be used tofill the hole. This treatment modality may create a betterload-supporting environment leading to long term healing. Electrical orheat stimulation may also be employed to stimulate the healing processof a chronically injured bone. Chemical, biochemical and/or biologicalstimulation may also be employed in SCP™. For instance, stimulation ofbone tissue in SCP™ may be enhanced via the use of cytokines and othercell signaling agents to trigger osteogenesis, chondrogenesis, and/orangiogenesis to perhaps reverse progression of osteoarthritis. Inaddition, some of the soft bone tissue may be compacted in order to aidin stimulation.

In yet another treatment modality, an implantable device may beimplanted into the subchondral bone to provide mechanical support to thedamaged or affected bone region, such as where an insufficiency fractureor stress fracture has occurred. The implant may help create a betterload distribution in the subchondral region. In the knees, the implantmay support tibio-femoral compressive loads. In addition, the implantmay mechanically integrate sclerotic bone with the surrounding healthybone tissue. The implant may be placed in cancellous bone, throughsclerotic bone, or under sclerotic bone at the affected bone region. Inorder to create a void or space for the implant, some of the soft bonetissue at or near the bone marrow lesion or defect may be compacted. Theimplant may also be configured as a bi-cortical bone implant. In oneembodiment, one side of the implant can be anchored to the peripheralcortex to create a cantilever beam support (i.e., a portion of theimplant is inserted into bone but the second end stays outside or nearthe outer surface of the bone). The implant may be inserted using aguide wire. In one example, the implant may be inserted over a guidewire. In another example, the implant may be delivered through a guideinstrument. Exemplary guide instruments, navigation, and targetingsystems are also disclosed in co-pending and co-owned U.S. patentapplication Ser. No. 12/950,230, filed Nov. 19, 2010 and entitled“INSTRUMENTS FOR TARGETING A JOINT DEFECT,” U.S. patent application Ser.No. 12/950,154, filed Nov. 19, 2010 and entitled “INSTRUMENTS FORVARIABLE ANGLE APPROACH TO A JOINT,” U.S. patent application Ser. No.12/950,114, filed Nov. 19, 2010 and entitled “COORDINATE MAPPING SYSTEMFOR JOINT TREATMENT,” U.S. patent application Ser. No. 12/950,061, filedNov. 19, 2010 and entitled “NAVIGATION AND POSITIONING INSTRUMENTS FORJOINT REPAIR,” the contents of which are herein incorporated in theirentirety by reference.

The implant may further be augmented with a PMMA or CaP cementinjection, other biologic agent, or an osteoconductive, osteoinductiveand/or osteogenic agent. The augmentation material may be introducedthrough the implant, around the implant, and/or apart from the implantbut at the affected bone region, such as into the lower region of a bonemarrow lesion or below the lesion. For example, the implant may act as aportal to inject the augmentation material into the subchondral boneregion.

While each of the above-mentioned treatment modalities may beadministered independent of one another, it is contemplated that anycombination of these modalities may be applied together and in any orderso desired, depending on the severity or stage of development of thebone defect(s). Accordingly, the present disclosure also providessuitable implantable fixation devices for the surgical treatment ofthese altered bone regions or bone defects, especially at thesubchondral level. Applicants have also discovered devices andinstruments that can be used in combination with cements or hardeningmaterials commonly used to repair damaged bone by their introductioninto or near the site of damage, either to create a binding agent,cellular scaffold or mechanical scaffold for immobilization,regeneration or remodeling of the bone tissue.

In general, the embodiments relate to implantable devices for thesurgical treatment of bone, and particularly to a bone defect at a jointregion, and even more particularly at the subchondral bone level of thejoint region. Provided are implantable devices made of bone material forimproved physiological and biological compatibility. The devices areconfigured to provide mechanical strength and structural integrity tobone tissue to be treated, while also being physiologically andbiologically compatible. In addition, the devices facilitate thedispersal of a flowable material such as a hardening or augmentationmaterial in the same area.

The present disclosure provides suitable implantable fixation devicesfor the surgical treatment of these altered bone regions or bonedefects, especially at the subchondral level. These implantable devicesare configured to provide mechanical strength and structural integrityto bone tissue to be treated, while also facilitating the dispersal ofhardening or augmentation material in the same area. In addition, theseimplantable devices are formed of bone material, such as allograftmaterial, thereby making them physiologically and biologicallycompatible as well as biomechanically similar to naturally occurringbone.

Turning now to the drawings, implantable devices particularly suitablefor implantation in certain areas of the bone, such as near theperiarticular surface or the subchondral bone area (usually within therange of about 2-15 mm from the bone's articular surface) are shown.FIG. 1 illustrates an exemplary embodiment of an implantable device ofthe present disclosure. Implantable device 10 can include a main body 16extending between a first, leading end 12 and a second, trailing end 14.The first, leading end 12 of the implantable device 10 can include atapered nose or tip 18 to facilitate ease of insertion to the targetsite. If so desired, however, the tip 18 may also be rounded or it maybe flattened.

In addition, a surface feature may be present on the main body 16 forenhanced bone tissue engagement with the target site. In the embodimentshown, the surface feature may comprise a rib or fin 20. One or morefins 20 can be provided in the present embodiment. The fins 20 may helpto facilitate a press-fit connection of the implantable device 10 to theinsertion site or cavity. The fins 20 of FIG. 1 may have a uniformheight across their length, or the fins 20 may have varying heightsacross their length to create a curved, wavy, or irregular pattern. Forexample, the fins 20 may be S-shaped, V or W-shaped to create a jaggedspine-like profile along the length of the main body 16. It iscontemplated that the surface feature may also include structuralelements such as threads, teeth, barbs, bumps, spikes, or other surfaceenhancements. These surface enhancements may serve as anti-migrationfeatures after implantation.

As previously mentioned, the implantable device 10 may further beaugmented with a flowable material, such as a bone cement oraugmentation material like a bone void filler as previously described,other biological agent, or an osteoconductive, osteoinductive and/orosteogenic agent like a bone graft material. The flowable material maybe introduced through the implantable device, around the implantabledevice, and/or apart from the implantable device but at the affectedbone region, such as into the lower region of a defect like a bonemarrow lesion. For example, the implantable device 10 may act as aportal for injecting the flowable material into the defect area, wherethe defect area could be in the subchondral bone region.

As shown, the main body 16 may include one or more recesses or flutes 22extending along the longitudinal axis of the implantable device 10. Theflutes 22 are flattened, depressed regions of the main body 16 andseparate the fins 20 around the circumference of the main body 16. Theimplantable device 10 may be cannulated and provided with a centralcanal or opening 30, as shown. The central opening 30 may have athreaded end 40 (see FIGS. 4A-4C) for attachment to a delivery tool orinjection system. Further the implantable device 10 may be fenestrated,with one or more pores or channels 24 provided on the flutes 22, witheach pore or channel 24 being in fluid communication with the centralopening 30 of the implantable device 10. The channels 24 enable the userto introduce a flowable material, such as a bone cement or augmentationmaterial as previously described, into the central opening 30 and allowthe material to extrude out of the channels 24 and into the recesses orflutes 22. The central opening 30 would enable the flowable material tobe introduced through the implantable device 10, while the channels 24would allow the material to be ejected around the implantable device 10.The flutes 22 around the main body 16 create voids or open space aroundthe implantable device 10 to accommodate the flowable material. Thepores or channels 24 can also provide access for bone ingrowth andvasculature permeation.

Although shown with a plurality of channels 24, each being similar insize, it is understood that the dimensions of the channels 24 may vary.For example, it is contemplated that the channels 24 may haveincremental sizes along the length of the main body 16. Also, thechannels 24 may have a predetermined spatial pattern, such as forexample, a staggered arrangement, instead of being coaxial. Further, inanother exemplary embodiment the implantable device 10 can includechannels 24 in only one section of the main body 16, thereby impartingdirectional control and enabling augmentation material to be extruded inonly that area of the implantable device 10. For instance, in oneembodiment the channels 24 may be isolated to the lower portion of themain body 16 and be provided in only the lower half of each of theflutes 22. In another embodiment, channels 24 may be provided on onlyone of the flutes 22. By selectively providing channels 24 in a discreteportion of the implantable device 10, the user is able to control thedirection in which the flowable material is extruded.

While the main body 16 is shown as being substantially cylindrical, itis understood that the main body 16 may be shaped so as to have varyingdiameters along its length. For instance, the main body 16 may have afigure “8” shape, a bowling pin shape, a U-shape, a crescent or C-shape,an I-beam shape, a rectangular or square shape, a star shape, orcorkscrew shape, etc. so long as it is suitable for insertion into bonetissue and has enough structural integrity to perform its intendedfunction of bridging a fracture or fissure, supporting bone regrowth orremodeling, and/or binding the bone tissue together to prevent furtherbreakdown or degeneration. The implantable device 10 may be formed of abone material such as allograft or cadaver bone, including cortical,cortico-cancellous, bi-cortical, tri-cortical, or sesamoid bonematerial. The bone material allows for improved physiological andbiological compatibility, since it mimics the patient's natural bonetissue. In addition, radiopaque markers may be employed with theimplantable device 10 for imaging possibilities.

However, while bone material provides certain desirable benefits to theimplantable device 10 as previously mentioned, a bone implant can alsobe relatively weak and brittle, and present challenges in its deliveryand ultimate placement, particularly inside bone tissue. As described inthe exemplary embodiment above, the cannulated and fenestrated allograftdevice 10 could be very fragile and break during insertion before thedevice 10 can be supported by a hardening material like cement. Toovercome this obstacle, various insertion and delivery tools for usewith the implantable device 10 of the present disclosure are alsoprovided.

FIGS. 2A-2C illustrate one exemplary embodiment of a tool of the presentdisclosure. As shown, inserter tool 100 may include a shaft 102 havingat one end a device-engaging portion 104 and at an opposite end a handleportion 106. The device-engaging portion 104 may comprise finger-likeprojections 108 extending out from the shaft 102 and separated by slots110 in between. The finger-like projections 108 may be configured toslide along, and reside inside the recesses 22 of the implantable device10, thereby allowing the inserter tool 100 to firmly support or grip theimplantable device 10 but without significantly increasing the overallouter diameter of the device 10. It is contemplated that each of theprojections 108 can be independently operational, such that the user maybe able to manipulate a projection 108 separately and independent of theother projections 108.

FIG. 2A shows the inserter tool 100 with its projections 108 extendinginside about halfway down the length of the flutes 22 of the implantabledevice 10, whereas FIG. 2B shows the inserter tool 100 fully engagedwith the implantable device 10. In this scenario, the projections 108cover the entire length of the flutes 22 and provide the maximumprotection to the implantable device 10 during implantation. Incontrast, FIG. 2C shows the inserter tool 100 retracted from theimplantable device 10 and with the projections 108 disengaged from theimplantable device 10, such as near the end of the implantation process.In this scenario, the projections 108 can be slid out of the flutes 22and the inserter tool 100 slightly rotated so that the projections 108are no longer aligned with the flutes 22. Accordingly, during thedelivery process the implantable device 10 may be entirely supportedwithin the device-engaging portion 104 of the inserter tool 100 untilthe projections 108 are retracted and the device 10 is released from theinserter tool 100 to its desired location.

FIGS. 3A-3Q illustrate one exemplary method of using the implantabledevice 10 and other exemplary embodiments of insertion and deliverytools of the present disclosure, in which the implantable device 10 maybe used to treat a bone defect in a bone 2 of a joint. As shown, thebone 2 may be a tibia of a knee joint, while the defect may be a bonemarrow lesion at the subchondral level below the articular surface 4.FIG. 3A shows a guidewire or pin 120 placed at the target area 6 of thebone 2 to be treated. FIG. 3B shows a cannulated reamer 140 slid overthe pin 120. The cannulated reamer 140 may be provided with a shapedcutting portion 142 for boring a cavity or hole 8 in the bone 2 forreceiving the implantable device 10, as further shown in FIG. 3C. Theshaped cutting portion 142 may have a geometry matching that of theimplantable device 10. The cannulated reamer 140 may be operatedmanually or it may be powered. After a sufficiently sized hole 8 hasbeen prepared, the cannulated reamer 140 may be removed, as illustratedin FIG. 3D, and then the pin 120 can next be removed. In addition, ithas been discovered that the bone tissue surrounding a bone marrowlesion tends to be relative soft (usually, edema is present) comparedwith normal, healthy bone tissue. Accordingly, the surgeon may alsocompact some of the soft bone tissue and then optionally insert animplant, such as implantable device 10, into the area adjacent to thecompacted bone tissue.

FIGS. 3E and 3F show exemplary embodiments of other inserter toolsincluding a delivery tube 160, delivery tool 180 and obturator 200. Thedelivery tube 160 may include a slot 164 at a tool-engaging end 162 forreleasable engagement with a notch 182 on the delivery tool 180. Ofcourse, other mechanisms for attachment and quick release may beemployed as is known in the art. At the opposite end of the deliverytube 160 extend guide fingers 168 that form the device-engaging portion166 of the delivery tube 160. These guide fingers 168 function in thesame manner as the projections 108 of inserter tool 100, and are able toslide in and out of the flutes 22 of the implantable device 10.

As further shown, an obturator 200 is provided having the same size andshape as the implantable device 10 to be delivered. The obturator 200 isintended as a metal or polymeric replica of the implantable device 10,and can be used to expand the cavity 8 or confirm that there is adequateroom to receive the implantable device 10. In addition, the obturator200 facilitates positioning of the delivery tube 160, as will be shownlater. The obturator 200 may be held by the guide fingers 168 of thedelivery tube 160, as illustrated.

Turning now to FIGS. 3G and 3H, the delivery tube 160, delivery tool 180and attached obturator 200 can be assembled together, and the deliverytube 160 with the obturator 200 can be placed completely into the boredhole 8 previously created. The delivery tube 160 is properly positionedwhen the obturator 200 is in the same position as desired for theimplantable device 10. Although not shown, it is contemplated that thedelivery tube 160 may have surface features such as teeth or barbs toanchor it to the bone 2.

Once the delivery tube 160 has been properly positioned and anchored tothe bone 2, the obturator 200 and the delivery tool 180 may be removed,leaving just the delivery tube behind, as illustrated in FIG. 31. Thisremoval step could be achieved by simply pulling the delivery tool 180(which is also attached to the obturator 200) straight out from thedelivery tube 160 and releasing the slot 164 of the delivery tube 160from the notch 182 of the delivery tool. As the partial cross-sectionalview of FIG. 3J depicts, the guide fingers 168 of the delivery tube 160remain positioned against the cavity 8 created in the bone 2. Thedelivery tube 160 itself provides a working channel through which theimplantable device 10 may be inserted into the cavity 8, and preventscollapse of the implantable device 10 during the process. In addition tosupporting the implantable device 10, the delivery tube 160 prevents orcontrols flow of any injected flowable materials through the implantabledevice 10.

FIGS. 3K and 3L illustrate the implantable device 10 of the presentdisclosure attached to a device insertion tool 220. The device insertiontool 220 may be cannulated, and comprise a main channel 222 onto whichis a telescoping channel 224. The telescoping channel 224 includes agrip 228 for manipulating the telescoping channel relative to the mainchannel 222. Although not shown, it is contemplated that the implantabledevice 10 may be threadedly attached to the device insertion tool 220 atthe distal end of the main channel 222. Using the device insertion tool220, the implantable device 10 is aligned with the delivery tube 160. Aswas shown in FIG. 31, the delivery tube 160 includes internal ribs 170that act as guide rails for insertion of the implantable device 10therethrough. Accordingly, the flutes 22 of the implantable device 10can be mated to the internal ribs 170 of the delivery tube 160 to alignthe device 10 for proper insertion.

Upon proper placement of the implantable device 10 inside the cavity 8,a flowable material such as cement may then be injected into theimplantable device 10 to strengthen the entire construct. Thetelescoping channel 224 of the device insertion tool 220 may be sliddown and engaged with delivery tube 160 so that the delivery tube 160 islocked to the telescoping channel 24, as shown in FIGS. 3M and 3N. Then,the grip 228 of the device insertion tool 220 may be pulled back, asshown in FIGS. 3O and 3P, to cause retraction of the delivery tube 160and guide fingers 168 from the bone 2. It is contemplated, of course,that the device delivery tool 220 could also allow modular movement ofthe guide fingers 168, such that the guide fingers 168 could beretracted in sync or independent of one another as desired to controlthe flow of material out of the implantable device 10. That is, thechannels 24 of the implantable device 10 may be selectively uncovered toallow extrusion of cement from only those uncovered channels 24.

In one embodiment, an injection port 240 may be provided with aLuerlok-type configuration for attaching the device delivery tool 220 tothe flowable material injection system. As shown in FIG. 3Q, the devicedelivery tool 220 may include a threaded opening 226 for receiving athreaded end 242 of the injection port 240. The opposite or injectionconnecting end 244 of the injection port 240 may be configured like aLuer port, for instance, to connect to the flowable material injectionsystem. The steps of retracting the guide fingers 168 and the injectionof flowable material may be done simultaneously, or step-wise in acontrolled manner.

Additionally, a slap hammer (not shown) may be provided to remove thedelivery tube 160 completely from the bone 2 at the end of theprocedure. Further a custom tamp (not shown) may be provided for properimpaction of the implantable device 10 into the bone cavity 8. The tampcould also be provided with an internal recess or cavity that maycontain an injection port. It is contemplated that the tamp could beconfigured with the dual purpose of serving as a slaphammer as well, byallowing the user to control the direction of force to be applied withthe instrument. Either one of these additional features may beintegrated into the device delivery tool 220.

FIGS. 4A-4C illustrate another exemplary embodiment of a method of usingthe implantable device 10 of the present disclosure. In this method, theinjection port 240 would be directly attached to the implantable device10, and make the implantable device 10 ready for cement injection. Asshown in FIGS. 4B and 4C, the threaded end 242 of the injection port 240could be threadedly attached to the implantable device 10 and allow amore direct connection between the cement injector and the implantabledevice 10. It should be noted that, while FIGS. 4A-4C show the second,trailing end 14 of the implantable device 10 exposed and outside of thebone 2, the implantable device 10 is intended to be positioned withinthe cavity 8. The depictions of the implantable device 10 extendingbeyond the bone 2 is purely for the illustrative purpose of showing theconnection between the implantable device 10 and the injection port 240only.

The implantable devices 10 of the present disclosure may be used torepair bone defects in a joint region such as the knee, shoulder, ankle,hip or other joint of the patient's body. The implantable devices may beuseful, for example, in repairing an insufficiency fracture of a bone ata joint.

While the implantable devices 10 have been described as being used withan injectable or flowable material, it is understood, however, thatthese implants shown and described herein may be used alone without anyinjectable or flowable material if so desired.

FIGS. 5A-5B illustrate another exemplary embodiment of an implantabledevice. As shown, the implantable device 50 may have similarities to theimplantable device 10 described above. Implantable device 50 can includea main body 56 extending between a first, leading end 52 and a second,trailing end 54. The first, leading end 52 of the implantable device 50can include a tapered nose or tip 58 to facilitate ease of insertion tothe target site. If so desired, however, the tip 58 may also be roundedor it may be flattened. In addition, a surface feature may be present onthe main body 56 for enhanced bone tissue engagement with the targetsite.

Like implantable device 10, the implantable device 50 may further beaugmented with a flowable material, such as a hardening material like abone cement or augmentation material, such as a bone void filler, aspreviously described, other biological agent, or an osteoconductive,osteoinductive and/or osteogenic agent like a bone graft material. Theflowable material may be introduced around the implantable device,and/or apart from the implantable device but at the affected boneregion, such as into the lower region of a defect like a bone marrowlesion.

As shown, the main body 56 can be substantially solid and may includeone or more recesses or flutes 62 extending along the longitudinal axisof the implantable device 50. The flutes 62 are depressed regions of themain body 56. The recesses 62 allow flowable material to be containedaround the periphery of the device 50.

While the main body 56 is shown as being substantially cylindrical, itis understood that the main body 56 may be shaped so as to have varyingdiameters along its length. For instance, the main body 56 may have afigure “8” shape, a bowling pin shape, a U-shape, a crescent or C-shape,an I-beam shape, a rectangular or square shape, a star shape, orcorkscrew shape, etc. so long as it is suitable for insertion into bonetissue and has enough structural integrity to perform its intendedfunction of bridging a fracture or fissure, supporting bone regrowth orremodeling, and/or binding the bone tissue together to prevent furtherbreakdown or degeneration.

Like implantable device 10, the implantable device 50 may be formed of abone material such as allograft or cadaver bone, including cortical,cortico-cancellous, bi-cortical, tri-cortical, or sesamoid bonematerial. The allograft material allows for improved physiological andbiological compatibility, since it mimics the patient's natural bonetissue.

FIG. 6A shows an inserter tool 300 with the device 50 of FIGS. 5A and5B. In addition, FIG. 6B shows the inserter tool 300 of FIG. 6A withdelivery tool 180. As shown in FIG. 6A, the inserter tool 300 isimplemented with its projections 308 extending inside and down thelength of the flutes 62 of the implantable device 50. FIG. 6B shows theinserter tool 300 fully engaged with the implantable device 50 and canbe used with the delivery tool 180 (previously shown above withreference to FIGS. 3E and 3F). As shown, the projections 308 may bedeployed to cover the entire length of the flutes 62 to provide themaximum protection to the implantable device 50 during implantation. Theprojections 308 may be configured to be independently operable to allowdirectional control over the flow of material to be injected around thedevice 50.

FIG. 7A shows the implantable device 50 of FIGS. 5A and 5B along with aninjection port 340 that can be employed with the device 50. FIG. 7Bshows the implantable device of FIGS. 5A and 5B connected to theinjection port 340. As shown, an injection port 340 can be directlyattached to the implantable device 50. As shown in FIGS. 7A and 7B, adevice-engaging portion 342 of the injection port 340 can be attached tothe implantable device 50. The device-engaging portion 342 of theinjection port 340 and the second, trailing end 54 of the implantabledevice 50 may both be shaped to provide complementary mating surfacesfor attachment (e.g., slightly tapered). Additionally, thedevice-engaging portion 342 may include a threaded section thatcomplements a threaded section (not shown) on the second trailing end 54of the device 50 in order to provide for a more secure connection. Theinjection port 340 can further include an injection connecting end 344on the opposite end from the device-engaging portion 342 for engaging aninjection system of a flowable material.

The injection port 340 allows for the introduction of a flowablematerial into and along the recesses 62 of the implantable device 50. AsFIG. 5B illustrates, portions of the recesses 62 at the second, trailingend 54 are grooved with a larger depth than the remainder of the recess62, in order to facilitate flow of the flowable material from itsinjection port into the recesses 62.

Other variations contemplated but not shown here include the addition ofa shoulder or flange on the second, trailing end 54 of the implantabledevice 50 in order to provide a mechanism for cortical bone contact. Theshoulder or flange would create an interference fit with the corticalbone.

The implantable device 50 of the present disclosure may be used torepair bone defects in a joint region such as the knee, shoulder, ankle,hip or other joint of the patient's body. The implantable devices may beuseful, for example, in repairing an insufficiency fracture of a bone ata joint.

While the implantable devices 50 have been described as being used withan injectable or flowable material, it is understood, however, thatthese implants shown and described herein may be used alone without anyinjectable or flowable material if so desired.

FIG. 8 illustrates yet another exemplary embodiment of an implantabledevice 350 of the present disclosure. Implantable device 350 shares thesame features as implantable device 50, with like elements beingrepresented by the same numeral following the prefix “3”. As shown,implantable device 350 can include a main body 356 extending between afirst, leading end 352 and a second, trailing end 354. The first,leading end 352 of the implantable device 350 can include a tapered noseor tip 358 to facilitate ease of insertion to the target site. If sodesired, however, the tip 358 may also be rounded or it may beflattened. In addition, a surface feature may be present on the mainbody 356 for enhanced bone tissue engagement with the target site, aspreviously mentioned.

Like implantable device 10 and 50, the implantable device 350 mayfurther be augmented with a flowable material, such as a hardeningmaterial like a bone cement or augmentation material, such as a bonevoid filler, as previously described, other biological agent, or anosteoconductive, osteoinductive and/or osteogenic agent like a bonegraft material. The flowable material may be introduced around theimplantable device, and/or apart from the implantable device but at theaffected bone region, such as into the lower region of a defect like abone marrow lesion.

As shown, the main body 356 can be substantially solid and may include arecess or flute 362 extending around the periphery of the implantabledevice 350. The flute 362 may be a depressed region of the main body356, and allow flowable material to be contained around the periphery ofthe device 350. The flowable material may be introduced at a single port364 represented by the opening where the recess 362 meets the second,trailing end 354 of the implantable device 350.

Implantable device 350 may have a shape other than cylindrical, asdescribed previously with devices 10 and 50. Furthermore, like devices10 and 50, implantable device 350 may be formed of a bone material suchas allograft or cadaver bone, including cortical, cortico-cancellous,bi-cortical, tri-cortical, or sesamoid bone material.

FIGS. 9 and 10 illustrated yet even more exemplary embodiments ofimplantable devices of the present disclosure. As shown in FIG. 9,implantable device 450 shares similar features with implantable device50, with like elements being represented by the same numeral followingthe prefix “4”. As shown, implantable device 450 can include a main body456 extending between a first, leading end 452 and a second, trailingend 454. The first, leading end 452 of the implantable device 450 caninclude a tapered nose or tip 458 to facilitate ease of insertion to thetarget site. If so desired, however, the tip 458 may also be rounded orit may be flattened. In addition, a surface feature may be present onthe main body 456 for enhanced bone tissue engagement with the targetsite, as previously mentioned.

Like implantable devices 10, 50 and 350, the implantable device 450 mayfurther be augmented with a flowable material, such as a hardeningmaterial like a bone cement or augmentation material, such as a bonevoid filler, as previously described, other biological agent, or anosteoconductive, osteoinductive and/or osteogenic agent like a bonegraft material. The flowable material may be introduced around theimplantable device, and/or apart from the implantable device but at theaffected bone region, such as into the lower region of a defect like abone marrow lesion.

As shown, the main body 456 can be substantially solid and may includerecesses or flutes 462 extending longitudinally along the periphery ofthe implantable device 450. Extending laterally around the periphery ofthe implantable device 450 are lateral recesses or flutes 464. Theflutes 462, 464 may be depressed regions of the main body 456, and allowflowable material to be contained around the periphery of the device450.

Implantable device 450 may have a shape other than cylindrical, asdescribed previously with devices 10, 50 and 350. Furthermore, likedevices 10, 50 and 350, implantable device 450 may be formed of a bonematerial such as allograft or cadaver bone, including cortical,cortico-cancellous, bi-cortical, tri-cortical, or sesamoid bonematerial.

In addition, the main body 456 may include a widened shoulder or flangeportion 466 having threads 458 on a portion thereon at the second,trailing end 454. This flange portion 466 provides a mechanism forcortical bone contact. The shoulder or flange portion 466 would createan interference fit between the implantable device 450 and corticalbone. A tool-engaging opening 470 may also be provided at the second,trailing end 454 for engaging an insertion tool. The opening 470 may bethreaded, for example.

FIG. 10 represents an alternative embodiment of the implantable device450 of FIG. 9 whereby the flanged portion is a cap 480 that is aseparate component from the main body 456 of the implantable device 450.As shown, the cap 480 may include a main body 482 extending from theflanged portion 484, on which there may be threads 486. Though notshown, the cap 480 may also include a tool-engaging opening forreceiving an insertion tool. The cap 480 and implantable device 450 mayengage each other in an interference fit, for example.

It is contemplated that a plug or cap may be provided with implantabledevices 10 described above in order to seal off the central opening 30and thereby prevent any flowable material contained within to leak out.Furthermore, a flanged portion may be provided with any one of theimplantable devices 10, 50, 350 described above in order to provide amechanism for attaching to cortical bone.

Another contemplated embodiment would provide a partially threaded,partial press-fit implantable device whereby the implantable device canbe first implanted by press-fitting, then removing the insertion toolfrom the device and turning the device in place so as to thread thedevice further into the insertion bore.

For all of the implantable devices 10, 50, 350, 450 described herein, itis also possible to first deposit an aliquot of flowable material into apredrilled bore prior to inserting the implantable device 10, 50, 350,and 450. In this exemplary method, the insertion of the device wouldpush excess flowable material out and around the device 10, 50, 350,450, settling into the recess or flute of the device.

Other embodiments of the invention will be apparent to those skilled inthe art from consideration of the specification and practice of thedisclosure provided herein. It is intended that the specification andexamples be considered as exemplary only, with a true scope and spiritof the disclosure being indicated by the following claims.

What is claimed is:
 1. A system for treatment of a subchondral bonedefect, comprising: an implantable device comprising a first, leadingend, a second, trailing end, and a main body extending between the ends,a central opening extending through the length of the main body, and atleast one channel in fluid communication with the central opening toallow extrusion of a flowable material from the central opening tooutside the main body, the device being formed of bone material andconfigured as both a mechanical support to stabilize the defect, and asa portal to disperse the flowable material to the defect, theimplantable device having a tapered tip at the first, leading end tofacilitate ease of insertion, and further comprising a plurality ofrecesses extending along the longitudinal axis of the main body, the atleast one channel being located within one of the recesses; and aninserter tool comprising a shaft having at one end a device-engagingportion and at an opposite end a handle portion, the device-engagingportion comprising a plurality of movable finger-like projectionsconfigured to slide along and reside within the recesses of theimplantable device to occlude the at least one channel and allow a firmgrip of the implantable device without significantly increasing theouter diameter of the device during insertion, each finger-likeprojection being capable of separate and independent sliding movementwith respect to the other projections to control access to the at leastone channel and the direction in which the flowable material isextruded.
 2. The system of claim 1, wherein the bone material is anallograft material.
 3. The system of claim 2, further including at leastone fin on the main body.
 4. The system of claim 3, wherein the at leastone recess comprises a depressed region on the main body.
 5. The systemof claim 3, wherein the at least one fin includes a plurality of fins,each of a pair of fins being separated by the recess.
 6. The system ofclaim 1, wherein the at least one channel resides within one of theplurality of recesses.
 7. The system of claim 6, wherein the at leastone channel further comprises a plurality of channels.
 8. The system ofclaim 7, wherein the channels reside in a predetermined arrangement onthe main body.
 9. A system for treatment of a subchondral bone defect,comprising: an implantable device comprising a first, leading end, asecond, trailing end, and a main body extending between the ends, thedevice being formed of bone material and configured as a mechanicalsupport to stabilize the defect, the implantable device having a taperedtip at the first, leading end to facilitate ease of insertion, andfurther comprising a plurality of recesses extending along thelongitudinal axis of the main body; and an inserter tool comprising adelivery tube including a telescoping channel for receiving theimplantable device, and having at one end a device-engaging portion andat an opposite end a handle portion, the device-engaging portioncomprising a plurality of movable finger-like projections configured toslide along and reside within the recesses of the implantable device toallow a firm grip of the implantable device without significantlyincreasing the outer diameter of the device during insertion, eachfinger-like projection being capable of separate and independent slidingmovement with respect to the other projections.
 10. The system of claim9, wherein the bone material is an allograft material.
 11. The system ofclaim 9, further including at least one fin on the main body.
 12. Thedevice of claim 11, further including a plurality of fins, each finbeing located between a pair of the recesses.
 13. The system of claim 9,wherein the at least one recess comprises a depressed region on the mainbody.